A silver rod and a SHE are dipped into a saturated aqueous solution of silver oxalate, Ag2C2O4, at 25°C. The measured potential difference between the rod and the SHE is 0.5812 V, the rod being positive. Calculate the solubility product constant for silver oxalate.

Answers

Answer 1

The solubility product constant (Ksp) is calculated as 2.392.

To solve this problem, we can use the Nernst equation:

Ecell = E°cell - (RT/nF) * ln(Q)

where:

Ecell is the measured potential difference between the rod and the SHE (0.5812 V)

E°cell is the standard cell potential

R is the ideal gas constant (8.314 J/(mol·K))

T is the temperature in Kelvin (25°C = 298 K)

n is the number of electrons transferred in the balanced redox reaction

F is Faraday's constant (96485 C/mol)

Q is the reaction quotient

In this case, the balanced redox reaction is:

Ag2C2O4(s) ⇌ 2Ag+(aq) + C2O4^2-(aq)

The solubility product constant (Ksp) for silver oxalate can be expressed as:

Ksp = [Ag+]^2 * [C2O4^2-]

Since the rod is positive, it means that Ag+ ions are being reduced to Ag(s) on the rod, so we can write:

E°cell = E°red,cathode - E°red,anode

The standard reduction potential for Ag+ to Ag(s) is 0.7996 V, and the standard reduction potential for C2O4^2- to CO2(g) is 0.1936 V.

Therefore, E°cell = 0.7996 V - 0.1936 V = 0.606 V

Now we can substitute all the values into the Nernst equation:

0.5812 V = 0.606 V - (8.314 J/(mol·K) * 298 K / (2 * 96485 C/mol)) * ln(Q)

Simplifying:

0.5812 V = 0.606 V - (0.0257 V) * ln(Q)

0.0257 V * ln(Q) = 0.606 V - 0.5812 V

0.0257 V * ln(Q) = 0.0248 V

ln(Q) = 0.0248 V / 0.0257 V

ln(Q) = 0.964

Q = e^(0.964)

Q ≈ 2.622

Since Q = [Ag+]^2 * [C2O4^2-], we can write:

[Ag+]^2 * [C2O4^2-] ≈ 2.622

The solubility product constant (Ksp) is the product of the concentrations of the ions at equilibrium, so we can assume that the concentrations are equal to each other:

[Ag+] ≈ [C2O4^2-]

Therefore, we can substitute [Ag+] for [C2O4^2-]:

[Ag+]^2 * [Ag+] ≈ 2.622

[Ag+]^3 ≈ 2.622

Taking the cube root of both sides:

[Ag+] ≈ (2.622)^(1/3)

[Ag+] ≈ 1.378

Therefore, the approximate solubility of silver oxalate is 1.378 M.

The solubility product constant (Ksp) can now be calculated as:

Ksp = [Ag+]^2 * [C2O4^2-] ≈ (1.378)^2 * (1.378) ≈ 2.392

Answer 2

The solubility product constant for silver oxalate at [tex]25\°C[/tex] is approximately [tex]\( 10^{-22.125} \)[/tex].

The solubility product constant [tex](\( K_{sp} \))[/tex] for silver oxalate can be calculated using the Nernst equation and the measured potential difference between the silver rod and the standard hydrogen electrode (SHE). The reaction occurring at the silver rod can be represented as:

[tex]\[ \text{Ag}_2\text{C}_2\text{O}_4(s) \rightleftharpoons 2\text{Ag}^+(aq) + \text{C}_2\text{O}_4^{2-}(aq) \][/tex]

The Nernst equation for this reaction at [tex]25\°C[/tex] is given by:

[tex]\[ E = E^{\circ} - \frac{0.0592}{n} \log \frac{1}{[\text{Ag}^+]^2[\text{C}_2\text{O}_4^{2-}]} \][/tex]

where [tex]\( E \)[/tex] is the measured potential (0.5812 V), [tex]\( E^{\circ} \)[/tex] is the standard reduction potential for the [tex]\( \text{Ag}^+ \)[/tex] / Ag couple, [tex]\( n \)[/tex] is the number of electrons transferred in the half-reaction (which is 2 for this reaction), and the concentrations of [tex]\( \text{Ag}^+ \)[/tex] and [tex]\( \text{C}_2\text{O}_4^{2-} \)[/tex] are equal to the solubility of silver oxalate since they come from its dissolution.

 First, we need to find the standard reduction potential [tex]\( E^{\circ} \)[/tex] for the [tex]\( \text{Ag}^+ \)[/tex] / Ag couple, which is 0.7996 V.

 Rearranging the Nernst equation to solve for the solubility \( S \), we get:

[tex]\[ S = [\text{Ag}^+] = [\text{C}_2\text{O}_4^{2-}] = 10^{\frac{(E^{\circ} - E)n}{0.0592}} \][/tex]

Plugging in the values:

[tex]\[ S = 10^{\frac{(0.7996 - 0.5812) \times 2}{0.0592}} \][/tex]

[tex]\[ S = 10^{\frac{0.2184 \times 2}{0.0592}} \][/tex]

[tex]\[ S = 10^{\frac{0.4368}{0.0592}} \][/tex]

[tex]\[ S = 10^{7.375} \][/tex]

[tex]\[ S \approx 10^{-7.375} \][/tex]

The solubility product constant [tex]\( K_{sp} \)[/tex] is given by:

[tex]\[ K_{sp} = [\text{Ag}^+]^2[\text{C}_2\text{O}_4^{2-}] \][/tex]

[tex]\[ K_{sp} = (S)^2(S) \][/tex]

[tex]\[ K_{sp} = (10^{-7.375})^2(10^{-7.375}) \][/tex]

[tex]\[ K_{sp} = 10^{-7.375 \times 3} \][/tex]

[tex]\[ K_{sp} = 10^{-22.125} \][/tex]


Related Questions

Place the following substances in order of increasing boiling point. Ne Cl2 O2

a. O2 < Cl2 < Ne
b. Cl2 < Ne < O2
c. Cl2 < O2 < Ne
d. Ne < O2 < Cl2
e. Ne < Cl2 < O2

Answers

Answer: = D

Explanation:

The atomic mass increases from Ne to O2 to Cl2 hence the boiling point also increases, therefore

Ne < O2 < Cl2

Write the balanced chemical equation for the combustion of ethane, , and answer these questions. (Use the lowest possible coefficients. Omit states of matter.) How many molecules of oxygen would combine with 16 molecules of ethane in this reaction

Answers

Answer:

1. 2C2H6 + 7O2 —> 4CO2 + 6H2O

2. 56moles of O2

Explanation:

Ethane undergo Combustion to produce CO2 and H20 according the equation below:

C2H6 + O2 —> CO2 + H2O

Let us balance the equation. There are 6 atoms of H on the left side and 2 atoms on the right side. It can be balanced by putting 3 in front of H2O as shown below:

C2H6 + O2 —> CO2 + 3H2O

There are 2 atoms of C on left and 1atom on the right. It can be balanced by putting 2 in front of CO2 as shown below:

C2H6 + O2 —> 2CO2 + 3H2O

There are a total of 7 atoms of O on the right and 2 atoms on the left. It can be balanced by putting 7/2 in front of O2 as shown below:

C2H6 + 7/2O2 —> 2CO2 + 3H2O

Now we multiply through by 2 to remove the fraction as shown below

2C2H6 + 7O2 —> 4CO2 + 6H2O

Now the equation is balanced

2. 2C2H6 + 7O2 —> 4CO2 + 6H2O

From the equation above,

2 moles of ethane(C2H6) combined with 7moles of O2.

Therefore, 16moles of ethane(C2H6) will combine with = (16x7)/2 = 56moles of O2

Consider the reaction: N2(g) + 2O2(g)2NO2(g) Using standard absolute entropies at 298K, calculate the entropy change for the system when 1.90 moles of N2(g) react at standard conditions. S°system = J/K Submit Answer

Answers

Explanation:

It is known that standard entropies for [tex]N_{2}(g)[/tex] is 191.6 J/mol K, [tex]O_{2}(g)[/tex] = 205 J/mol K, and [tex]NO_{2}(g)[/tex] is 239.7 J/mol K at 298 K.

Therefore, we will calculate the value of [tex]\Delta S^{o}_{reaction}[/tex] from standard absolute entropies as follows.

     [tex]\Delta S^{o}_{reaction} = \sum \Delta S^{o}_{products} - \sum \Delta S^{o}_{reactants}[/tex]

                   = 2 mole of [tex]NO_{2}(g)[/tex] - 1 mole of [tex]N_{2}(g)[/tex] + 2 mole of [tex]O_{2}(g)[/tex]

                   = [tex]2 \times 239.7 J/mol K - 1 \times 191.6 J/mol K + 2 \times 205 J/mol K[/tex]

                   = -122.2 J/K

The entropy change for 1.90 moles of [tex]N_{2}(g)[/tex] reacting is as follows.

        [tex]\Delta S^{o}_{system}[/tex] = 1.90 moles of [tex]N_{2}(g) \times 122.2 J/K/ 1 \text{mol of} N_{2}(g)[/tex]

                           = 232.18 J/K

Thus, we can conclude that the entropy change for the given system is 232.18 J/K.

Calculate the relative atomic mass of this sample of Germanium, giving your answer to two decimal places. ......................................................................................................................... ......................................................................................................................... ......................................................................................................................... .........................................................................................................................

Answers

Answer:

Germanium is an element in the same group with Carbon and Silicon. The atomic number is 32. The relative atomic mass is usually measured with the Sample of an isotope. In this case Germanium has a relative atomic mass of 72.63

Answer:

The relative atomic mass of the sample of Germanium is 72.89 u

Explanation:

For a sample of germanium we have the following compositions:

m70Ge = 70 u

%70Ge = 22.6%

m72Ge = 72 u

%72Ge = 25.45%

m74Ge = 74 u

%74Ge = 36.73%

m76Ge = 76 u

%76Ge = 15.22%

To calculate the atomic mass of Germanium we must add all the atomic masses of its isotopes multiplied by its percentage of abundance and all this divided by 100, in this way:

mGe = [(m70Gex%70Ge)+(m72Gex%72Ge)+(m74Gex%74Ge)+(m76Gex%76Ge)]/100

replacing values:

mGe = [(70x22.6)+(72x25.45)+(74x36.73)+(76x15.22)]/100 = 72.89 u

An aqueous solution of sodium sulfate is allowed to react with an aqueous solution of barium nitrate. What is the coefficient of the solid in the balanced equation

Answers

Answer: The coefficient of the solid in the balanced equation is 1.

Explanation:

A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.

The balanced chemical equation is:

[tex]Na_2SO_4(aq)+Ba(NO_3)_2(aq)\rightarrow BaSO_4(s)+2NaNO_3(aq)[/tex]

Thus a coefficient of 1 is placed in front of the solid.

The coefficient of the solid in the balanced equation is 1.

The double substitution reaction is a reaction in which ion exchange takes place. Salts that are soluble in water are indicated by the symbol (aq), and salts that are insoluble in water and remain solid are represented by (s) according to the chemical formula.

The balanced chemical equation is:

            Ba(NO3)2 + Na2SO4 → BaSO4 + NaNO3

Thus, the coefficient of the solid in the balanced equation is 1.

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13. In animals, nitrogenous wastes are produced mostly from the catabolism of
A. phospholipids and glycolipids
B. proteins and nucleic acids.
C. starch and cellulose
D. triglycerides and steroids
E. fatty acids and glycerol

Answers

Answer:

The answer is B

Explanation:

Determine the change in entropy for 2.7 moles of an ideal gas originally placed in a container with a volume of 4.0 L when the container was expanded to a final volume of 6.0 L at constant temperature.

Answers

Answer:

The value of entropy change for the process [tex]dS = 0.009 \frac{KJ}{K}[/tex]

Explanation:

Mass of the ideal gas = 0.0027 kilo mol

Initial volume [tex]V_{1}[/tex] = 4 L

Final volume [tex]V_{2}[/tex] = 6 L

Gas constant for this ideal gas ( R ) = [tex]R_{u} M[/tex]

Where [tex]R_{u}[/tex] = Universal gas constant = 8.314 [tex]\frac{KJ}{Kmol K}[/tex]

⇒ Gas constant R = 8.314 × 0.0027 = 0.0224 [tex]\frac{KJ}{K}[/tex]

Entropy change at constant temperature is given by,

[tex]dS = R log _{e} \frac{V_{2}}{V_{1}}[/tex]

Put all the values in above formula we get,

[tex]dS = 0.0224 log _{e} [\frac{6}{4}][/tex]

[tex]dS = 0.009 \frac{KJ}{K}[/tex]

This is the value of entropy change for the process.

Suppose a current of 60. A flows through a copper wire for 22.0 minutes. Calculate how many moles of electrons travel through the wire. Be sure your answer has the correct unit symbol and the correct number of significant digits.

Answers

Answer:  0.821 moles

Explanation:

Moles of electron = 1 mole

According to mole concept:

1 mole of an atom contains [tex]6.022\times 10^{23}[/tex] number of particles.

We know that:

Charge on 1 electron = [tex]1.6\times 10^{-19}C[/tex]

Charge on 1 mole of electrons = [tex]1.6\times 10^{-19}\times 6.022\times 10^{23}=96500C[/tex]

To calculate the charge passed, we use the equation:

[tex]I=\frac{q}{t}[/tex]

where,

I = current passed = 60 A

q = total charge = ?

t = time required = 22.0 minutes =[tex]22.0\times 60=1320sec[/tex]

Putting values in above equation, we get:

[tex]60A=\frac{q}{1320}\\\\q={60A}\times {1320s}=79200C[/tex]

As 96500 C contains = 1 mole of electrons

79200 C contains = [tex]\frac{1}{96500}\times 79200 =0.821[/tex] mole of electrons

Thus 0.821 moles of electrons travel through the wire.

Consider the following mechanism for the decomposition of NO2Cl to NO2 and Cl2: (1) NO2Cl ⇌ NO2 + Cl (2) NO2Cl + Cl → NO2 + Cl2 (a) Use steady-state approximation to express the rate of Cl2 production. Select the single best answer

Answers

Final answer:

The rate of Cl2 production can be determined using the steady-state approximation, which states that the rate of the forward reaction in the first step is equal to the rate of the reverse reaction. Therefore, the rate of Cl2 production is given by the rate of the forward reaction of step 1. This can be expressed as k1 [NO2Cl] [Cl].

Explanation:

The rate of Cl2 production can be determined using the steady-state approximation. According to the given mechanism, the first step is in equilibrium, so the forward and reverse reaction rates are equal. This allows us to express the rate of the forward reaction of step 1 as:

rate of forward reaction of step 1 = k1 [NO2Cl] [Cl]

Since the reverse reaction of step 1 is negligible, the overall rate of Cl2 production is equal to the rate of the forward reaction of step 1. Therefore, the rate of Cl2 production is given by:

rate of Cl2 production = k1 [NO2Cl] [Cl]

Final answer:

To express the rate of Cl2 production using the steady-state approximation, one must balance the rate of chlorine atom creation with its consumption and solve for its concentration in terms of the reactants and rate constants. This value is then used in the rate equation for Cl2 production.

Explanation:

The question pertains to the mechanism of the decomposition of nitryl chloride (NO2Cl) to nitrogen dioxide (NO2) and chlorine gas (Cl2). Since the steady-state approximation is used, we consider the intermediate species such as chlorine atoms (Cl) to be in a steady state, meaning their concentrations do not change over time. The provided steps do not correspond directly to the decomposition of NO2Cl, but they outline a similar mechanism which can be analyzed in the same manner using steady-state approximation.

If we follow a similar approach for NO2Cl decomposition, we would set the rate of creation of Cl equal to the rate of its consumption. This would lead to a system of equations that can then be solved to express the rate of Cl2 production in terms of the concentrations of the reactants and the rate constants of the elementary steps.

The rate of reaction (2) can be determined using the rate law, which is determined experimentally. However, since we are not given any experimental data or rate law, we cannot provide a specific answer.

To summarize, to find the rate of Cl2 production in the decomposition of NO2Cl, we need the rate law for reaction (2). Without the rate law, we cannot determine the specific rate of Cl2 production.

Air is about 78.0% nitrogen molecules and 21.0% oxygen molecules. Several other gases make up the remaining 1% of air molecules. What is the partial pressure of the other gases in air (excluding oxygen and nitrogen) at an atmospheric pressure of 0.90 atm

Answers

Answer:

The partial pressure of the other gases is 0.009 atm

Explanation:

Step 1: Data given

Air is about 78.0% nitrogen molecules and 21.0% oxygen molecules and 1% of other gases.

The atmospheric pressure = 0.90 atm

Step 2: Calculate mol fraction

If wehave  100  moles of air, 78 moles will be nitrogen,

21  moles will be  oxygen, and  1  mol will be other gases.

Mol fraction = 1/100 = 0.01

Step 3: Calculate the partial pressure of the other gases

Pgas = Xgas * Ptotal

⇒ Pgas = the partial pressure = ?

⇒ Xgas = the mol fraction of the gas = 0.01

⇒Ptotal = the total pressure of the pressure = 0.90 atm

Pgas = 0.01 * 0.90 atm

Pgas = 0.009 atm

The partial pressure of the other gases is 0.009 atm

A system at equilibrium has two aqueous products and two aqueous reactants. An additional amount of one of the products is added to the system. After the addition, which of the following will change?Select the correct answer below:a. the amount of the added productb. the amount of the other productc. the amounts of the reactantsd. all of the above

Answers

Final answer:

If an extra amount of a product is added to a system at equilibrium, the system will shift towards the reactants to counteract this change. This shift can cause changes in the amounts of all substances involved, including the added product, the other product, and the reactants.

Explanation:

When an extra amount of a product is added to a system at equilibrium, the system shifts to counteract this change and re-establish equilibrium, as described by Le Châtelier's principle. Specifically, the system will shift in the direction that reduces the excess amount of the product, i.e., towards the reactants. With this shift, the quantities of all substances in the system can change.

Therefore, the appropriate answer is d. all of the above. Adding more of one product will indeed increase the amount of that product initially (a), but the system will shift to remove the added product by moving towards the reactants. In this process, the amount of the other product may also change as it is consumed or generated (b), and the amounts of reactants will also adjust as they are generated or consumed (c).

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Even though we have known of many nuclear energy technologies for about one century some of these technologies have not yet been fully developed. Obtaining energy from thorium remains a challenge for many reasons. In a reactor, thorium is bombarded with neutrons and becomes U-233 and then U-234, which can undergo fission and produce energy. Complete the following U-234 fission reaction. Hint: Do not ignore the amount of energy given off by the reaction! 234.0 tlu . i37 154Xe + 3?Sr + 3 1.0087n + 180 MeV

Answers

Answer: The nuclear fission reaction of U-234.043 is written below.

Explanation:

In a nuclear reaction, the total mass and total atomic number remains the same.

For the given fission reaction:

[tex]^{234.043}_{92}\textrm{U}\rightarrow ^{137.159}_{54}\textrm{Xe}+^{A}_{38}\textrm{Sr}+3^{1.0087}_0\textrm{n}+180MeV[/tex]

To calculate A:

Total mass on reactant side = total mass on product side

234.043 = 137.159 + A + 3(1.0087)

A = 93.858

Now, the chemical equation becomes:

[tex]^{234.043}_{92}\textrm{U}\rightarrow ^{137.159}_{54}\textrm{Xe}+^{93.858}_{38}\textrm{Sr}+3^{1.0087}_0\textrm{n}+180MeV[/tex]

Hence, the nuclear fission reaction of U-234.043 is written above.

One way to represent this equilibrium is: N2O4(g)2NO2(g) Indicate whether each of the following statements is true, T, or false, F. AT EQUILIBRIUM we can say that: 1. The concentration of NO2 is equal to the concentration of N2O4. 2. The rate of the dissociation of N2O4 is equal to the rate of formation of N2O4. 3. The rate constant for the forward reaction is equal to the rate constant of the reverse reaction. 4. The concentration of NO2 divided by the concentration of N2O4 is equal to a constant.

Answers

Answer:

1. The concentration of [tex]NO_2[/tex] is equal to the concentration of [tex]N_2O_4[/tex] : False

2. The rate of the dissociation of [tex]N_2O_4[/tex] is equal to the rate of formation of [tex]N_2O_4[/tex]: True

3. The rate constant for the forward reaction is equal to the rate constant of the reverse reaction: False

4. The concentration of [tex]NO_2[/tex] divided by the concentration of [tex]N_2O_4[/tex] is equal to a constant : False

Explanation:

[tex]N_2O_4(g)\rightleftharpoons 2NO_2(g)[/tex]

The concentrations of reactant and product is constant and not equal.

The rate of forward and backward reactions are equal. Thus rate of the dissociation of [tex]N_2O_4[/tex] is equal to the rate of formation of [tex]N_2O_4[/tex]

For a reversible reaction, the equilibrium constant for the forward reaction is inverse of the equilibrium constant for the backward reaction and not equal.

Equilibrium constant is the ratio of the concentration of products to the concentration of reactants each term raised to its stochiometric coefficients.

[tex]K_c=\frac{[NO_2]^2}{[N_2O_4]}[/tex]

Final answer:

Statements 1 and 3 are False, and 2 and 4 are True.  At equilibrium, the rate of formation and dissociation of N₂O₄ are equal but their concentrations are not necessarily the same. Rate constants for forward and reverse reactions are different yet define the equilibrium constant. The concentration ratio of NO₂ to N₂O₄ is constant at a given temperature.

Explanation:

When dinitrogen tetroxide (N₂O₄) is in equilibrium with nitrogen dioxide (NO₂), the following statements can be made:

1. The concentration of NO₂ is equal to the concentration of N₂O₄. False - The stoichiometry of the reaction is 1:2, so for every molecule of N₂O₄ that dissociates, two molecules of NO₂ are formed.2. The rate of the dissociation of N₂O₄ is equal to the rate of formation of N₂O₄. True - At equilibrium, the rate of the forward reaction (dissociation of N₂O₄) is equal to the rate of the reverse reaction (formation of N₂O₄).3. The rate constant for the forward reaction is equal to the rate constant of the reverse reaction. False - The rate constants for the forward and reverse reactions are generally different, but their ratio is constant at a given temperature, defining the equilibrium constant.4. The concentration of NO₂ divided by the concentration of N₂O₄ is equal to a constant. True - At equilibrium, this ratio is equal to the equilibrium constant (Keq) for the reaction at a given temperature.

A specimen of a 4340 steel alloy with a plane strain fracture toughness of 54.8 MPa(50 ksi) is exposed to a stress of 1205 MPa(174800psi) . (a) If the largest surface crack is 0.8 mm (0.03150 in.) long, determine the critical stress ?c. (b) Will this specimen experience fracture? Assume that the parameter Y has a value of 0.99.

Answers

Explanation:

(a)  Formula for critical stress is as follows.

         [tex]\sigma_{c} = \frac{k_{IC}}{\tau \sqrt{\pi \times a}}[/tex]

Here,  [tex]K_{IC}[/tex] = 54.8

          [tex]\tau[/tex] = 0.99

            a = 0.8 mm = [tex]0.8 \times 10^{-3}[/tex] m

Putting the given values into the above formula as follows.

          [tex]\sigma_{c} = \frac{k_{IC}}{\tau \sqrt{\pi \times a}}[/tex]

                       = [tex]\frac{54.8}{0.99 \times \sqrt{3.14 \times 0.8 \times 10^{-3}}}[/tex]

                       = 1107 MPa

Hence, value of critical stress is 1107 MPa.

(b)    Applied stress value is given as 1205 MPa and since it is more than the critical stress (1107 MPa) as a result, a fracture will occur.

Lab group B determines that 0.003 moles of bicarbonate was present in their portion of an antacid tablet. How many grams of bicarbonate are in their tablet? Report your answer to 3 decimal places.

Answers

Answer:

There are 0.183 grams of bicarbonate in their tablet

Explanation:

Step 1: Data given

0.003 moles of bicarbonate was present in their portion of an antacid tablet

Bicarbonate = HCO3-

Molar mass of bicarbonate = 61.02 g/mol

Step 2: Calculate mass bicarbonate

Mass bicarbonate = moles bicarbonate * molar mass bicarbonate

Mass bicarbonate = 0.003 moles * 61.02 g/mol

Mass bicarbonate = 0.183 grams

There are 0.183 grams of bicarbonate in their tablet

A student has 500.0 mL of a 0.1133 M aqueous solution of BaI2 to use in an experiment. She accidentally leaves the container uncovered and comes back the next week to find only a solid residue. The mass of the residue is 28.28 g. Determine the chemical formula of this residue.

Answers

Answer:

[tex]BaI_2\ ^.6H_2O[/tex]

Explanation:

Hello,

In this case, by knowing the volume and the molarity of the barium iodide, is it possible to compute the residue's mass as shown below:

[tex]m_{BaI_2}=0.500L*0.1133\frac{molBaI_2}{L}*\frac{391.136gBaI_2}{1molBaI_2} =22.16gBaI_2[/tex]

Nevertheless, the obtained value is lower than the obtained by 6.133 g which means that mass corresponds to water forming a hydrate. In such a way, one could know how many waters in form of hydrate remain with the residue by a trial-error procedure as shown below:

[tex]m=28.28g=0.500L*0.1133\frac{molBaI_2}{L}*\frac{(391.136+18)gBaI_2\ ^.H_2O}{1molBaI_2} =23.17g\rightarrow No\\m=28.28g=0.500L*0.1133\frac{molBaI_2}{L}*\frac{(391.136+2*18)gBaI_2\ ^.2H_2O}{1molBaI_2} =24.20g\rightarrow No\\m=28.28g=0.500L*0.1133\frac{molBaI_2}{L}*\frac{(391.136+3*18)gBaI_2\ ^.3H_2O}{1molBaI_2} =25.22g\rightarrow No\\m=28.28g=0.500L*0.1133\frac{molBaI_2}{L}*\frac{(391.136+4*18)gBaI_2\ ^.4H_2O}{1molBaI_2} =26.24g\rightarrow No\\[/tex]

[tex]m=28.28g=0.500L*0.1133\frac{molBaI_2}{L}*\frac{(391.136+5*18)gBaI_2\ ^.5H_2O}{1molBaI_2} =27.26g\rightarrow No\\m=28.28g=0.500L*0.1133\frac{molBaI_2}{L}*\frac{(391.136+6*18)gBaI_2\ ^.6H_2O}{1molBaI_2} =28.28g\rightarrow Yes\\[/tex]

Therefore, the formula is barium iodide hexahydrate:

[tex]BaI_2\ ^.6H_2O[/tex]

Best regards.

Acetylenic compounds may be used as dienophiles in the Diels-Alder reaction. Write the structure for an adduct that you expect from the reaction of 1,3-butadiene with hexafluoro-2-butyne:

Answers

Answer:

Explanation:

An electron-donating heteroatom substituent at position-2 of a furan promotes regiospecific opening of the 7-oxa bridge of the Diels-Alder cycloadduct with hexafluoro-2-butyne, producing a 4-heterosubstituted 2,3-di(trifluoromethyl)phenol building block in a single step. The phenol and heteroatom substituent are easily transformed to the corresponding iodide or triflate that readily undergoes Heck, Suzuki, and Stille reactions to install a variety of substituents in high yields. This methodology provides a facile and general synthesis of 1,4-disubsituted 2, 3-di(trifluoromethyl)benzenes.

Final answer:

The Diels-Alder reaction of 1,3-butadiene with hexafluoro-2-butyne would form a six-membered ring with a hexafluoroalkyl side group, yielding a bicyclic compound.

Explanation:

The Diels-Alder reaction between 1,3-butadiene and hexafluoro-2-butyne would yield a six-membered ring product, specifically a bicyclic compound due to the formation of a cyclohexene derivative where the double bond is part of the ring and the hexafluoroalkyl group is attached to two adjacent carbons in the ring. It involves the 1,3-butadiene acting as the diene and the hexafluoro-2-butyne acting as the dienophile in an intermolecular reaction. The Diels-Alder reaction creates two new sigma bonds and a pi bond across the alkene and the alkyne to form the new cyclohexene ring.

A chemist adds of a sodium carbonate solution to a reaction flask. Calculate the mass in grams of sodium carbonate the chemist has added to the flask. Be sure your answer has the correct number of significant digits.

Answers

The question is incomplete, here is the complete question:

A chemist adds 180.0 mL of a 1.42 M sodium carbonate solution to a reaction flask. Calculate the mass in grams of sodium carbonate the chemist has added to the flask. Be sure your answer has the correct number of significant digits.

Answer: The mass of sodium carbonate that must be added are 40.9 grams

Explanation:

To calculate the mass of solute, we use the equation used to calculate the molarity of solution:

[tex]\text{Molarity of the solution}=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (in mL)}}[/tex]

Molar mass of sodium carbonate = 106 g/mol

Molarity of solution = 1.42 M

Volume of solution = 180.0 mL

Putting values in above equation, we get:

[tex]1.42mol/L=\frac{\text{Mass of sodium carbonate}\times 1000}{160g/mol\times 180}\\\\\text{Mass of sodium carbonate}=\frac{160\times 1.42\times 180}{1000}=40.9g[/tex]

Hence, the mass of sodium carbonate that must be added are 40.9 grams

PCL was mixed with gelatin to make a blend for elctrospun fibrous scaffold encapsulating growth factor that was admixed in the polymer solution and then filled in the syringe for electrospinning. Three scaffolds were made with (A: only PCL), (B: PCL:gelatin=3:1), (C: PCL:gelatin = 1:1). The scaffolds were immersed in PBS at 37 °C! and its degradation rate was noted: Scaffold A, B and C degraded 1%, 25% and 50% respectively, in 21 days. Assuming the growth factor is trapped and cannot freely diffuse out of the scaffold. Assuming, growth factor release is dependent on scaffold degradation A. Which scaffold can be used for delivering growth factor (encapsulated in the scaffold) needed to be delivered in first 7 days of incubation in an in-vivo experiment and why? (5pts) B. The scaffold A and C were prepared and freeze dried. Their weights were Dry weight of A: 10 mg Dry weight of C: 10 mg Both (A and C) the scaffolds were kept in PBS for 7 days at 37 °C. The scaffolds were freeze dried and their weight was recorded. Weight of A after degradation: 9.967 mg Weight of C after degradation: 8.33 mg Calculate the percentage weight remaining for A and C scaffold and comment on why one scaffold degraded faster than the other.

Answers

Answer:

Explanation:

First PCL to form a scaffold, combined with gelatin.

They are made by first three forms A) made by just PCL.B) made by gelatin ratio PCL is 3:1 and last is C) made by gelatin PCL.

The decoration rate is 1%, 25% and 50% respectively.

A) Growth factor is stuck in 21 days, and can not spread. In this case in vivo experiment for 7 days used highly degradable scaffold use the ability to break down due to decomposition in vivo degradation rate depends on the scaffold's acid byproduct impact.

B) the amount of scaffolded degradation.

First, with scaffold A.

10 mg scaffold weight A= 1 per cent degradation.

Following degradation wt is 9.967=? Degradation per cent.

So, degradation (9.967* 1)/10= 0.9967 per cent.

Likewise for C) scaffold c 10 mg wt. Loss of 50 per cent.

After wt 8.33=? Degradation per cent.

Degradation (8.33* 50)/10=41.65 per cent.

Scaffold c degrades significantly, since the loss of wt is even greater.

How many mL of 0.05 M sodium acetate should be added to 100 mL of 0.05M acetic acid to make a buffer of pH 5.1? What is the molarity of the resulting buffer with respect to acetate (Acetate + Acetic Acid)? pKa acetic = 4.76

Answers

Explanation:

Let us assume that volume of acetic acid added is V ml.

So,   [tex][CH_{3}COOH] = \frac{0.05 \times 100}{100 + V}[/tex]

and,   [tex][CH_{3}COONa] = \frac{0.05 \times V}{100 + V}[/tex]

Expression for the buffer solution is as follows.

     pH = [tex]pK_{a} + log \frac{[CH_{3}COONa]}{[CH_{3}COOH]}[/tex]

     5.1 = [tex]4.76 + log \frac{0.05 \times V}{0.05 \times 100}[/tex]

         0.34 = log V - 2

         log V = 2.34

or,        V = 218.77 ml

Now, we will calculate the molarity of the buffer with respect to acetate as follows.

  = [tex][CH_{3}COO^{-}] + [CH_{3}COOH][/tex]

  = [tex]\frac{0.05 \times 218.77}{318.77} + \frac{0.05 \times 100}{318.77}[/tex]

  = 0.0499 M

or,  = 0.05 M (approx)

Thus, we can conclude that molarity of the resulting buffer with respect to acetate is 0.05 M.

Final answer:

To make a buffer of pH 5.1 using 0.05 M acetic acid, the Henderson-Hasselbalch equation is used to calculate the amount of 0.05 M sodium acetate needed. The result is based on achieving the correct ratio of acetate ion to acetic acid. The molarity of the resulting buffer depends on the total moles of acetate and acid in the final solution volume.

Explanation:

To determine how many mL of 0.05 M sodium acetate should be added to 100 mL of 0.05M acetic acid to make a buffer of pH 5.1, we can use the Henderson-Hasselbalch equation, which is pH = pKa + log([A-]/[HA]), where [A-] is the concentration of the acetate ion and [HA] is the concentration of acetic acid. Given that the pKa of acetic acid is 4.76, plugging in the pH 5.1 gives us the equation 5.1 = 4.76 + log([A-]/[0.05]).

Solving for [A-], we find that the ratio of [A-] to [HA] needed is approximately 2.2. Since the volume of the acetic acid solution is 100 mL and its concentration is 0.05M, to achieve the desired ratio, the amount of sodium acetate needed can be calculated based on the molarity and the final volume of the solution. The resulting molarity of the buffer with respect to acetate (acetate + acetic acid) will be determined by the total moles of acetate ions and acetic acid divided by the total volume of the solution after the addition of sodium acetate.

Which of the following is a false statement about the isotopes carbon-12 (12C) and carbon-13 (13C)? Please choose the correct answer from the following choices, and then select the submit answer button. 12C and 13C have the same atomic weight. 12C and 13C have different numbers of neutrons. 13C has one more electron than 12C. 13C has more subatomic particles in its nucleus than 12C. 13C has the same atomic number as 12C.

Answers

The given isotopes of carbon, i.e., 12C and 13C, have the same number of protons but the number of neutrons differs. So, the statement 12C and 13C have different numbers of neutrons, is correct.

Isotopes are members of the same element's family but have variable numbers of neutrons despite having the same number of protons.

The element carbon can have different isotopes, based on the number of neutrons.

The isotopes of carbon include, C10, C11, C12, C13, C14, C15, and C16.

The given isotope, 12C and 13C, possess similar chemical properties and the same atomic number.

But the mass of the 13C isotope of carbon is more, because it possesses, one extra neutron, as compared to the 12C isotope of carbon.

Thus, the statement about the isotopes, “12C and 13C have different numbers of neutrons”, is correct.

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Final answer:

The statement that 13C has one more electron than 12C is incorrect. Both carbon-12 (12C) and carbon-13 (13C) isotopes have the same number of electrons due to both having the same atomic number. They only differ in the number of neutrons they possess.

Explanation:

The statement '13C has one more electron than 12C' is false. Both isotopes, carbon-12 (12C) and carbon-13 (13C) have the same atomic number '6', which represents the number of protons and, under stable conditions, also views it as the same number of electrons.

So, while 12C and 13C indeed differ in the number of neutrons (12C has 6 neutrons and 13C has 7), they possess the same number of protons and electrons. Furthermore, their atomic weights are different as a result of the difference in the number of neutrons. The atomic weight of 12C is closer to 12 and that of 13C is closer to 13.

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In a coffee-cup calorimeter experiment, 10.00 g of a soluble ionic compound was added to the calorimeter containing 75.0 g H2O initially at 23.2°C. The temperature of the water increased to 31.8°C. What was the change in enthalpy for the dissolution of the compound? Give your answer in units of joules per gram of compound. Assume that the specific heat of the solution is the same as that of pure water, 4.18 J ⁄ (g ⋅ °C).

Answers

Final answer:

The change in enthalpy for the dissolution of the compound is 344.11 J/g.

Explanation:

In a coffee-cup calorimeter experiment, the change in enthalpy for the dissolution of a compound can be determined using the equation q = mCΔT, where q is the amount of heat absorbed or released, m is the mass of the compound, C is the specific heat of the solution, and ΔT is the change in temperature. Given that the initial temperature of the water is 23.2°C and the final temperature is 31.8°C, the change in temperature is ΔT = 31.8°C - 23.2°C = 8.6°C.

Since 10.00 g of the compound was added to 75.0 g of water, the total mass of the solution is 75.0 g + 10.00 g = 85.0 g.

Using the equation q = mCΔT, where C is the specific heat of water (4.18 J/(g·°C)), the amount of heat involved in the dissolution can be calculated as q = (85.0 g)(4.18 J/(g·°C))(8.6°C) = 3,441.14 J.

The change in enthalpy for the dissolution of the compound is thus 3,441.14 J/10.00 g = 344.11 J/g of the compound.

Calculate the volume (in mL) of 6.25 x 10-4 M ferroin solution that needs to be added to a 10.0 mL volumetric flask and diluted with deionized (DI) water in order to prepare a calibration standard solution with a concentration of 2.50 x 10-5 M ferroin. As part of your preparation for performing this experiment, repeat this calculation for each of the calibration standards you will need to prepare and record the information in your lab notebook so that you have it ready during the lab session. Group of answer choices 0.200 mL 0.400 mL 0.600 mL 0.800 mL none of the above

Answers

The volume V2 is 0.400 ml

Explanation:

The dilution equation is the product of initial values of molarity and volume which is equal to the product of final values of molarity and volume.

The dilution equation is given by

                          M1 [tex]\times[/tex] V1 = M2 [tex]\times[/tex] V2

where,

M represents the molarity of the solution  

V represents the volume of the solution

M1 and V1 are the initial values  of the solution

M2 and V2 are the final values of the solution

                            M1 [tex]\times[/tex] V1 = M2 [tex]\times[/tex] V2

               (2.5 [tex]\times[/tex] [tex]10^{-5}[/tex]) [tex]\times[/tex] 10 = (6.25 [tex]\times 10^{-4}[/tex]) [tex]\times[/tex] V2  

                                    V2 = 2.5 [tex]\times 10^{-4}[/tex] / (6.25 [tex]\times 10^{-4}[/tex])  

                                    V2 = 0.4

    The volume V2 is 0.400 ml

The volume of solution required is 0.400 mL.

In this case, we have to use the dilution formula;

C1V1 = C2 V2

In this case;

C1 =  6.25 x 10-4 M

V1 = ?

C2 = 2.50 x 10-5 M

V2 = 10.0 mL

Making V1 the subject of the formula;

V1 = C2V2/C1

V1 = 2.50 x 10-5 M x 10.0 mL/6.25 x 10-4 M

V1 = 0.400 mL

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Determine whether the following reaction is a Lewis acid/base reaction and if so, what is the Lewis acid: Fe3+(aq) + 6 CN−(aq) → Fe(CN)63−(aq) Group of answer choices This is not a Lewis acid/base reaction It is a Lewis acid/base reaction, and Fe3+ is the Lewis acid It is a Lewis acid/base reaction, and CN- is the Lewis acid

Answers

Answer: It is a Lewis acid/base reaction, and [tex]Fe^{3+}[/tex] is the Lewis acid.

Explanation:

According to the Lewis concept, an acid is defined as a substance that accepts electron pairs and base is defined as a substance which donates electron pairs.

[tex]Fe^{3+}[/tex] can readily accept electrons and thus act as a lewis acid which is short of electrons.

[tex]CN^-[/tex] can readily lose electrons and thus act as a lewis base which has excess of electrons.

It is a Lewis acid/base reaction, and [tex]Fe^{3+}[/tex] is the Lewis acid.

The aggregation of nonpolar molecules or groups in water is thermodynamically due to the ________.

A. increased entropy of the water molecules.
B. decreased enthalpy of the system.
C. very strong van der Waals forces among the nonpolar molecules or groups.
D. increased entropy of the nonpolar molecules when they associate.

Answers

Answer:

A. Increased entropy of the water molecules.

Explanation:

Entropy is the quantitative measure of disorder or randomness in a system or element. In thermodynamics, entropy or hydrophobic effect is the free energy change of water enclosing a solute. Hence the existing negative free charges enhances the effect of hydrophilicty hence the aggregation of non-polar molecules.

Final answer:

The aggregation of nonpolar molecules in water is primarily due to the increased entropy of the water molecules, as they rearrange themselves to accommodate nonpolar molecules.

Explanation:

The aggregation of nonpolar molecules or groups in water is thermodynamically due to the increased entropy of the water molecules. When nonpolar molecules or groups are added to water, water molecules arrange themselves in order to minimize the disruption of hydrogen bonds, which increases the entropy of water. In other words, the introduction of nonpolar substances leads to a more disordered and random arrangement of water molecules, increasing the system's overall entropy.

Options B, C, and D although relevant, are not the primary reason. While enthalpy may decrease due to aggregation and Van der Waals forces might influence nonpolar association, the primary factor contributing to the phenomenon is the change in water's entropy.

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Determine the rate constant for each of the following fi rst-order reactions, in each case expressed for the rate of loss of A: (a) A S B, given that the concentration of A decreases to one-half its initial value in 1000. s; (b) A S B, given that the concentration of A decreases from 0.67 molL1 to 0.53 molL1 in 25 s; (c) 2 A S B C, given that [A]0 0.153 molL1 and that after 115 s the concentration of B rises to 0.034 molL1

Answers

Explanation:

The integrated first law is given by :

[tex][A]=[A]_o\times e^{-k\times t}[/tex]

Where:

[tex][A]_o[/tex] = initial concentration of reactant

[A] = concentration of reactant after t time

k = rate constant

a)

[tex][A_o]=x[/tex]

[tex][A]=\frac{x}{2}[/tex]

t = 1000 s

[tex]\frac{x}{2}=x\times e^{-k\times 1000 s}[/tex]

Solving for k:

[tex]k=0.06934 s^{-1}[/tex]

The rate constant for this reaction is [tex]0.06934 s^{-1}[/tex].

b)

[tex][A_o]=0.67 mol/L[/tex]

[tex][A]=0.53 mol/L[/tex]

t = 25 s

[tex]0.53 mol/L=0.67 mol/L\times e^{-k\times 25s}[/tex]

Solving for k:

[tex]k=0.009376 s^{-1}[/tex]

The rate constant for this reaction is [tex]0.009376 s^{-1}[/tex].

c) 2 A → B +C

[tex][A_o]=0.153 mol/L[/tex]

[tex][A]=?[/tex]

[tex][B]=0.034 mol/L[/tex]

According to reaction, 1 mole of B is obtained from 2 moles of A.

Then 0.034 mole of B will be obtained from:

[tex]\frac{2}{1}\times 0.034 mol= 0.068 mol[/tex] of A

So, the concentration left after 115 seconds:

[tex][A]=0.153 mol/L-0.068 mol/L=0.085 mol/L[/tex]

t = 115 s

[tex]0.085mol/L=0.53 mol/L\times e^{-k\times 115 s}[/tex]

Solving for k:

[tex]k=0.01592 s^{-1}[/tex]

The rate constant for this reaction is [tex]0.01592 s^{-1}[/tex].

Grey Goose ® vodka has an alcohol content of 40.0 % (v/v). Assuming that vodka is composed of only ethanol and water answer the following questions. Note: The molar masses of water and ethanol are 18.0 g and 46.0 g, respectively. The densities of water, ethanol, and this vodka mixture are 1.00 g/mL, 0.789 g/mL, and 0.935 g/mL, respectively

a. Calculate the molarity of ethanol in this vodka, assuming that water is the solvent.
b. Calculate the percent by mass of ethanol % (m/m) in this vodka.
c. Calculate the molality of ethanol in this vodka assuming that water is the solvent.
d. Calculate the mole fractions of ethanol and water in this vodka.
e. Calculate the vapor pressure, in torr, of this vodka at 25.0 oC if the vapor pressures of pure water and ethanol are 23.8 torr and 45.0 torr, respectively?

Answers

Explanation:

Grey Goose vodka has an alcohol content of 40.0 % (v/v).

Volume of vodka = V = 100 mL

This means that 40.0 mL of alcohol is present 100 mL of vodka.

Volume of ethanol=V' = 40.0 mL

Mass of ethanol = m

Density of the ethanol = d = 0.789 g/mL

[tex]m=d\times V' = 0.789 g/ml\times 40.0 mL=31.56 g[/tex]

Volume of water = V''= 100 ml - 40.0 mL = 60.0 mL

Mass of water = m'

Density of the water = d' = 1.00 g/mL

[tex]m'=d'\times V'' = 1.00 g/ml\times 60.0 mL=60.0 g[/tex]

a.)

Moles of ethanol = n= [tex]\frac{31.56 g}{46g/mol}=0.6861 mol[/tex]

Volume of vodka = V = 100 mL = 0.100 L ( 1mL=0.001 L)

Molarity of the ethanol:

[tex]=\frac{0.6861 mol}{0.100 L}=6.861 M[/tex]

6.861 M the molarity of ethanol in this vodka.

b) Mass of ethanol = 31.56 g

Moles of ethanol = n= [tex]\frac{31.56 g}{46g/mol}=0.6861 mol[/tex]

Volume of vodka = V = 100 mL

Mass of vodka = m

Density of the water = D = 0.935 g/mL

[tex]M=D\times V=0.935 g/ml\times 100 ml=93.5 g[/tex]

The percent by mass of ethanol % (m/m):

[tex]\frac{31.56 g}{93.5 g}\times 100=33.75\%[/tex]

33.75% is the percent by mass of ethanol % (m/m) in this vodka.

c)

Moles of ethanol = n= [tex]\frac{31.56 g}{46g/mol}=0.6861 mol[/tex]

Mass of solvent that is water = 60.0 g = 0.060 kg ( 1g = 0.001 kg)

Molality of ethanol in vodka :

[tex]m=\frac{0.6861 mol}{0.060 kg}=11.435 m[/tex]

11.435 m is the molality of ethanol in this vodka.

d)

Moles of ethanol = [tex]n_1=\frac{31.56 g}{46g/mol}=0.6861 mol[/tex]

Moles of water = [tex]n_2=\frac{60.0 g}{18 g/mol}=3.333 mol[/tex]

Mole fraction of ethanol = [tex]\chi_1[/tex]

[tex]\chi_1=\frac{n_1}{n_1+n_2}=\frac{0.6861 mol}{0.6861 mol+3.333 mol}[/tex]

= 0.1707

Mole fraction of water = [tex]\chi_2[/tex]

[tex]\chi_2=\frac{n_2}{n_1+n_2}=\frac{3.3333 mol}{0.6861 mol+3.333 mol}[/tex]

= 0.8290

e)

The vapor pressure of vodka = P

Mole fraction of ethanol = [tex]\chi_1=0.1707[/tex]

Mole fraction of water = [tex]\chi_2=0.8290[/tex]

The vapor pressures of ethanol  = [tex]p_1=45.0 Torr[/tex]

The vapor pressures of pure water = [tex]p_2=23.8Torr[/tex]

[tex]P=\chi_1\times p_1+\chi_2\times p_2[/tex]

[tex]P=0.1707\times 45.0torr+0.8290\times 23.8 Torr=27.41 torr[/tex]

The vapor pressure of vodka is 27.41 Torr.

Be sure to answer all parts. Zinc is an amphoteric metal, meaning it reacts with both acids and bases. The standard reduction potential is −1.36 V for the following reaction: (1)Zn(OH)42−(aq) + 2e− → Zn(s) + 4OH−(aq) Calculate the formation constant Kf for the reaction: (2)Zn2+(aq) + 4OH−(aq) ⇌ Zn(OH)42−(aq)

Answers

Answer:

[tex]1.86*10^{20[/tex]

Explanation:

The equation for the reaction is:

[tex]Zn^{2+}_{(aq)} + 4OH^-_{(aq)}[/tex]     ⇄     [tex]Zn(OH)^{2-}_{4(aq)}[/tex]

Oxidation can be defined as the addition of oxygen, removal of hydrogen and/or loss of electron during an electron transfer. Oxidation process occurs at the anode.

On the other hand; reduction is the removal of oxygen, addition of hydrogen and/ or the process of electron gain during an electron transfer. This process occurs at  the cathode.

The oxidation-reduction process with its standard reduction potential is as follows:

[tex]Zn(OH)^{2-}_{4(aq)} + 2e^- ----->Zn_{(s)} +4OH^-_{(aq)}[/tex]            [tex]E^0_{anode} = -1.36 V[/tex]

At the zinc electrode (cathode); the reduction process of the reaction with its standard reduction potential is :

[tex]Zn^{2+}_{(aq)} +2e^- -----> Zn_{(s)}[/tex]                  [tex]E^0_{cathode} = -0.76 V[/tex]

The standard cell potential [tex]E^0_{cell}[/tex] is given as:

[tex]E^0_{cell}=E^0_{cathode}-E^0_{anode}[/tex]

[tex]E^0_{cell}[/tex] = -0.76 V - (- 1.36 V)

[tex]E^0_{cell}[/tex] = -0.76 V + 1.36 V

[tex]E^0_{cell}[/tex] = +0.60 V

Now to determine the formation constant [tex]k_f[/tex] of the [tex]E^0_{cell}[/tex] ; we use the expression:

[tex]E^0_{cell}[/tex] = [tex]\frac{RT}{nF}Ink_f[/tex]

where;

[tex]E^0_{cell}[/tex] = +0.60 V

R = universal gas constant = 8.314 J/mol.K

T = Temperature @ 25° C = (25+273)K = 298 K

n = numbers of moles of electron transfer = 2

F = Faraday's constant = 96500 J/V.mol

[tex]+ 0.60 V = \frac{(8.314)(298)}{n(96500)} Ink_f[/tex]

[tex]+0.60 V = \frac{(0.0257)}{n}Ink_f[/tex]

[tex]+0.60V = \frac{0.0592}{n}log k_f[/tex]

[tex]logk_f = \frac{+0.60V*n}{0.0592}[/tex]

[tex]logk_f = \frac{+0.60V*2}{0.0592}[/tex]

[tex]logk_f = 20.27[/tex]

[tex]k_f= 10^{20.27}[/tex]

[tex]k_f = 1.86*10^{20}[/tex]

Therefore, the formation constant [tex]k_f[/tex] for the reaction is = [tex]1.86*10^{20[/tex]

a metal sample has a mass of 7.56 g. the sample is placed into a graduated cylinder previously filled with 20.00 mL of water. If the final volume in the cylinder is 21.68 mL, what is the density of the substance?

Answers

Answer:

4.5g/ml

Explanation:

metal sample has a mass = 7.56 g

cylinder previously filled with water = 20.00 mL

final volume in the cylinder =  21.68 mL

[tex]density = \frac{mass}{V_f - V_i}[/tex]

[tex]density = \frac{7.56}{(21.68 - 20.00)}[/tex]

density = 4.5g/ml

With respect to NAD+ and NADP+, which electron carrier is generally preferred for anabolic reactions? Group of answer choices Just NAD+ Just NADP+ Either of these Neither of these

Answers

Answer:

Just NADP+.

Explanation:

Two main type of biochemical reaction are anabolic reaction and catabolic reaction. Anabolic reactions joins the small molecules to form the large products.

The electron carrier may be defined as the molecule that has the ability to transport the electron from one molecule to the other molecule. NADP+ acts as electron carrier in the synthesis of molecule especially in the cholesterol metabolism. NAD+ acts as electron carrier in the catabolic reactions.

Thus, the correct answer is option (2).

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The government has the ability to influence the level of output in the short run using monetary and fiscal policy. There is some disagreement as to whether the government should attempt to stabilize the economy. Which of the following are arguments in favor of active stabilization policy by the government? Check all that apply. Shifts in aggregate demand are often the result of waves of pessimism or optimism among consumers and businesses. Changes in government purchases and taxation must be passed by both houses of Congress and signed by the president. The Fed can effectively respond to excessive pessimism by expanding the money supply and lowering interest rates. Businesses make investment plans many months in advance. Which of the following are examples of automatic stabilizers? Check all that apply. The federal funds rate Corporate income taxes The discount rate Which european country sent the explorers who first made contact with latin america? Mastery of pragmatics allows children to change styles of speech, or "codes," depending on the audience. What code are children likely to use with their teachers? The Pollution ProblemBy: Roberto BererraUnfortunately, pollution is like air: its everywhere! Pollution is the introduction of harmful substances into the environment that can cause damage and harm to humans, animals, and the environment. It takes on a number of different forms, from chemicals and garbage to something as seemingly innocent as light or noise.2 Pollution comes from a variety of sources. In addition, it alters, changes, and even destroys a variety of places. For example, exhaust from cars pollutes the air. When it rains, runoff from fertilizers and pesticides, which farmers use to help crops grow, can pollute the water in oceans, rivers, lakes, and streams. Garbage dumped in landfills is not only an eyesore, but also a source of harmful gases that can damage the earths atmosphere. Light pollution, which comes in the form of bright streetlights or signs, disrupts the view of the night sky. Noise pollution caused by cars, trucks, and machines interrupts the natural sounds of the world around us, such as birds singing or leaves rustling.3 The types of pollution and their effects vary greatly. At the same time, however, they are related; each type of pollution affects the other types. An example of the connection between different types of pollution is acid rain. Acid rain is caused mostly by sulfur or nitrogen emissions given off by sources such as car exhaust and the burning of fossil fuels such as coal. These harmful chemicals rise into the atmosphere where they react with other compounds and then fall as an acidic form of rain, sleet, or snow. Acid rain damages plants and buildings, contaminates soil and water, and has a negative effect on animals, fish, and even humans.4 Pollution has other effects, too. Breathing toxic air or drinking polluted water can cause humans and animals to develop health problems that can be serious and sometimes deadly. The deaths of too many members of a certain species of animal can upset the local ecosystem, or the area in which they live. As a result, weather patterns and climates can also change.Which conclusion is BEST supported by the information in the text?A)An example of the connection between different types of pollution is acid rain. Acid rain is caused mostly by sulfur or nitrogen emissions given off by sources such as car exhaust and the burning of fossil fuels such as coal. They harm the ozone.B)Pollution is everywhere, but there are ways to reduce. By walking or biking, instead of driving, air pollution can be reduced. People can also buy and eat organic foods to support clean farming. Finding new uses for old things also helps.C)Pollution is unhealthy for the planet and there is nothing we can do about it. For many years, scientists have warned people about pollution, but nobody seemed to care or want to change their behaviors. Our planet is now polluted.D)Acid rain and noise pollution are among many types of pollution faced by our planet. When Earth becomes too polluted for people to live, we may consider starting colonies on other planets, like Mars. Scientists are considering that now. A light bulb has a lifetime that is exponential with a mean of 200 days. When it burns out a janitor replaces it immediately. In addition there is a handyman who comes at times of a Poisson process at rate .01 and replaces the bulb as "preventive maintenance." (a) How often is the bulb replaced? (b) In the long run what fraction of the replacements are due to failure? The ____________ is considered the autonomic control center of the body due to its regulation of hormone secretion, thermoregulation, food and water intake, and circadian rhythms. 4 Friends each took a different path walking from the Lunchroom to the gymnausium. Rowan walked 150 yards, Janelle walked 429 feet 8 inches, Domingo walked 130 yards 2 feet, And Lydia walked 460 feet. Who walked the farthest? ________ is a type of polyploidy that arises from the hybridization between two different species. When Sarita first moved into her dorm room, she would get distracted by other students chatting in the hall outside her room. After two months of repeated exposure to conversations in the hallway, Sarita does not get distracted anymore. Sarita has learned through:______.a. habituation.b. sensitization.c. observational learning.d. operant conditioning. On January 1, 2015, a company had 250,000 shares of its $2 par value common stock outstanding. On March 1, the company sold an additional 500,000 shares on the open market at $20 per share. the company issued a 20% stock dividend on May 1. On August 1, the company purchased 280,000 shares and immediately retired the stock. On November 1, 400,000 shares were sold for $25 per share. What is the weighted-average number of shares outstanding for 2015? a. 477,777 b. 344,444 c. 750,000 d. 1,020,000 e. none of these answers are correct please help me again David manages a Shoney's restaurant. He is considering staying open later in the evening. For David, the variable costs associated with staying open longer hours will include all of the following except A light plane is headed due south with a speed of 200 km/h relative to still air. After 1.00 hour, the pilot notices that they have covered only 137 km and their direction is not south but 15.0 east of south. What is the wind velocity? A 2.0-in-thick slab is 10.0 in wide and 12.0 ft long. Thickness is to be reduced in three steps in a hot rolling operation. Each step will reduce the slab to 75% of its previous thickness. It is expected that for this metal and reduction, the slab will widen by 3% in each step. If the entry speed of the slab in the first step is 40 ft/min, and roll speed is the same for the three steps.Calculate: a) lenghtb) exit velocity of the final slab DFW Security Services targets high income professionals with custom-designed security systems. These systems are positioned as the premier systems availabe on the market. DFW Security employes a highly refined marketing mix to support its intended market position with target customers. What has just been described amounts to DFWs marketing mix? The Ohio State Studies narrowed the independent dimensions of leader behavior to two that substantially accounted for most of the leadership behavior described by employees: consideration and ________.A. Initiating structureB. Constructing visionC. EmpathyD. CharismaE. Employee-orientation visibility